Illuminated felorus



Patented Sept. 5, 1944 UNITED STATES PATENT OFFICE 2,357,282 ILLUMINATED IELOUSy Frank H. Parks, Portland, Oreg. v Application February 8, 1943, `Serial No. 475,133

1 claim. (ci. 24o-2.1) v

v This invention relates generally to navigation instruments, and particularly to an illuminated pelorus.

The. main object of this invention is to provide a pelorus with a means for illuminating only that portion of its dial where a reading is taken, and to make it possible to easily control the amount of illumination.'

The second object is to provide an illuminated pelorus which will not employ atransparent dial having general illumination which detracts from the efficiency of the illumination and is unnecessarily hazardous when exposed to the observation of an enemy.

rThe third object is to construct a device of the class described which will not in any way interfere with the normal operation of the pelorus, and at the same time will be easy to manufacture and maintain in proper working order.

The fourth object is to eliminate the glass dial, which is subjectto breakage, and which will be substantially water-proof.

I accomplish these and other 'objects in the manner set forth in the following specification, as illustrated in the accompanying drawing, in which:

Fig. l is a plan of a pelorus with parts broken away in section. n

Fig. 2 is a vertical section taken along the line 2--2 in Fig. 1.

Fig. 3 is a fragmentary section taken along the.

line 3-3 in Fig. 2.

Similar numerals refer to the same or similar parts throughout the'several views.

Referring in detail to the drawing, there is shown a cylindrical base I having a closed bottom I I. A lead weight I2 is placed on the bottom I I to provide stability for. the device. On the cylindrical portion Il! is a cylindrical wall whose uppermost end is formed a ilange I4 from which radiate the spokes i5 around which yis formed the circular rim I6 havingV a shoulder recess i1 for'the support of the metallic disc or dial I3 on which are calibrated a circle, together with the values in degrees 20, as well as the divisions of the circle in eighthssuch as S, SW, W, etc.

The cylindrical portion I3 is provided with a bottom 22 which is held in place by the two bolts 23 who-se lower ends are imbedded in the lead' i2 and whose upper ends are provided with the nuts 24 on the top side of ,the floor 22. The cylindrical portions l0 and I3 are preferably shaped as shown to insure a concentric relationship and to form a water shed at the joint of the two members.

Integral with the floor whose reduced upper end 21 whose recessed upper side shouldered center 29 of the dial IB.

22 is apost4 25 upon 26 is mounted a collar 28 receives the The dial I3 is provided with an externally threaded tubular stern 3D at the base of which is a flange 3l, the

i stem 30 is secured to the dial I8.

I3 around f the degrees I9 of Y edv on the upper end of sirable to provide The tubular sternk 30 has mounted thereon the hub 32 from which project the alidade arms33 and 34 which may rotate with relation tothe dial I 8 or be fixed with relation thereto by means of the knurled clamping nut 35 which is threadthe stem 30 and bearsV against the top side of the hub 32 enabling itlto be clamped against the flange 3l. The upper end 36 of the post 25 is threaded to receive the knurled clamping nut 31 by means lof which the alidade arms 33 and 34, as well as the dial I8, may be held against rotation provided the nut 35 is also tightened.

The rearmost alidade arm tially square side opening 38 formed therein while on its outer end are formed the upright standards 33 on whose horizontal pin 4D is mounted the foldable leaf 4I having a sighting slot 42 formed therein. The slot 42 enables one to sight in a vertical plane across the center of the dial I8 and normal thereto.

The forward arm 33 resembles the arm 34 but is hollowedon lthe under side of the portion 43 whose rearmost end 44 is sloping and acts as a reflecting surface. The dial IB is perforated or provided with the slots 45 through which light is secured to the floor 22.

33 is provided with the upright standards 49 on whose pin 53 is mounted the folded leaf 5I provided with a slot 52 in which is mounted the sighting vane 53. yIt is dethe leaf 5I with a folding leaf 54 containing a colored transparency for use in bright sunlight or in the face of strong artificial light.

It will be u derstood that the circular rim I6 can rock on the trunnions 55 which are mounted inthe ring 56 whose trunnion 51 may be suitably mounted on any support in order to hold the bottom I I in ar free position so that the foldable leaves 4I and 5I will automatically remain in a vertical position. A ne wire 58 is placedacross the opening 59 in the arm 33 in a radial direction and close to the calibrated surface of the dial I8.

Extending downwardly through the post 25 is the stem 66 on whose upper end is secured the button 6I of a combined rheostat and switch consisting of a disc 62 of insulating material which is keyed on the lower end of the stem 63 and carries a resistance wire 63, one end of which is grounded by a wire 64 to thestem 53. YA brush 64 bears against the resistance wire 63 as the button 6I is turned. The brush 64a is connected by a wire 65 to a lamp 66 whose second wire 61 The forward arm 34 has a substan-l is connected to the source of electrical energy 68 which in this case is illustrated as being grounded to the stem B0 by means of the wire 69.

It can be seen from the foregoing, that in the operation of this device, the mariner when taking a reading under poor light conditions merely turns the button 6I until current ows through the Wire 63 providing themaximum resistance It is desirable to provide the leaf 5| with a spirit level 1| to insure the vane 53, and consequently the sighting slot 42, being in the same vertical plane passing through the line of observation.

No attempt is being made herein to claim the invention of the pelorus, but only the improved form of illuminated pelorus as is set forth in the appended claim.

I claim:

In a device of the class described, the Combination of a supporting ring, an opaque dial revolvable on said ring, an alidade mounted on said dial, a folding leaf at each end of said alidade, one end of said alidade having a light conducting channel formed on its under side and having a substantially rectangular aperture formed at the outer end of said arm communicating with said channel, an electric lamp disposed beneath said dial, and a combined switch and rheostat for controlling the ow of current to said lamp, said dial having openings formed therein, all of which are covered by said alidade except those which register with said channel, whereby light lmay pass from said lamp through the dial openings, along said channel and into the aperture of the alidade arm for the purpose of illuminating that portion of the dial contained within said aperture.

FRANK H. PARKS. 

